Arduino类出现多重函数定义警告，编译失败求助

编译失败，错误信息如下：

Command.cpp.o (symbol from plugin)*: In function CommandClass::CommandClass()
(.text+0x0)*: multiple definition of CommandClass::JsonToClass(String)
Command.cpp.o (symbol from plugin)*: (.text+0x0): first defined here

CommandClass类位于项目引入的Arduino库SWRAntennaLib中，项目文件SWRArduino2.vcxproj的ItemGroup条目如下：

<ItemGroup>
    <ClCompile Include="..\..\libraries\SWRAntennaLib\src\Command.cpp" />
    <ClCompile Include="..\..\libraries\SWRAntennaLib\src\Enms.cpp" />
    <ClCompile Include="AllBands.cpp" />
    <ClCompile Include="Band.cpp" />
    <ClCompile Include="FileReqestHandler.cpp" />
    <ClCompile Include="FileRequest.cpp" />
    <ClCompile Include="Frequency.cpp" />
    <ClCompile Include="Json.cpp" />
    <ClCompile Include="LCD.cpp" />
    <ClCompile Include="RTClock.cpp" />
    <ClCompile Include="SDCard.cpp" />
    <ClCompile Include="Stepper.cpp" />
    <ClCompile Include="SWRArduino2.ino">
      <FileType>CppCode</FileType>
      <DeploymentContent>true</DeploymentContent>
    </ClCompile>
  </ItemGroup>
  <ItemGroup>
    <None Include="src\arduino folders read me.txt">
    </None>
  </ItemGroup>
  <ItemGroup>
    <ProjectCapability Include="VisualMicro" />
  </ItemGroup>
  <ItemGroup>
    <ClInclude Include="..\..\libraries\SWRAntennaLib\src\Command.h" />
    <ClInclude Include="..\..\libraries\SWRAntennaLib\src\DefinedValues.h" />
    <ClInclude Include="..\..\libraries\SWRAntennaLib\src\Enms.h" />
    <ClInclude Include="AllBands.h" />
    <ClInclude Include="Band.h" />
    <ClInclude Include="FileReqestHandler.h" />
    <ClInclude Include="FileRequest.h" />
    <ClInclude Include="Frequency.h" />
    <ClInclude Include="Json.h" />
    <ClInclude Include="LCD.h" />
    <ClInclude Include="RTClock.h" />
    <ClInclude Include="SDCard.h" />
    <ClInclude Include="Stepper.h" />
    <ClInclude Include="__vm\.SWRArduino2.vsarduino.h" />
  </ItemGroup>

Command.h代码 #

#include <ArduinoJson.h>
#include<RTClib.h>
class CommandClass
{
 protected:
     void JsonToClass(String json);
     String _commandAction;
     String _request;
     String _timeStamp;

 public:
     CommandClass();
     CommandClass(String command);
     CommandClass(String action, String request);
     const String ToJson();
     String CommandAction(String value = "");
     String Request(String value = "");
     String TimeStamp(String value = "");
};

extern CommandClass Command;

Command.cpp代码 #

#include "Command.h"

CommandClass::CommandClass(){}
CommandClass::CommandClass(String command)
{
    _timeStamp = DateTime().TIMESTAMP_FULL;
    JsonToClass(command);
}

CommandClass::CommandClass(String action, String request)
{
    _timeStamp = DateTime().TIMESTAMP_FULL;
    _commandAction = action;
    _request = request;
}

void CommandClass::JsonToClass(String json) {
    // Deserialize the JSON document
    JsonDocument doc;
    DeserializationError error = deserializeJson(doc, json);
    if (error) {
        Serial.print(F("deserializeJson() failed: "));
        Serial.println(error.f_str());
        return;
    }
    // Command values
    _commandAction = doc["commandAction"].as<String>();
    _request = doc["request"].as<String>();
    _timeStamp = doc["timeStamp"].as<String>();
}


const String CommandClass::ToJson() {
    // Create a new JSON document
    JsonDocument doc;
    // Set the values
    doc["commandAction"] = _commandAction;
    doc["request"] = _request;
    doc["timeStamp"] = _timeStamp;
    // Serialize the JSON document
    String json;
    serializeJson(doc, json);
    return json;
}

String CommandClass::CommandAction(String value) {
    if (value != "") {
        _commandAction = value;
    }
    return _commandAction;
}
String CommandClass::Request(String value) {
    if (value != "") {
        _request = value;
    }
    return _request;
}

String CommandClass::TimeStamp(String value) {
    if (value != "") {
        _timeStamp = value;
    }
    return _timeStamp;
}

CommandClass Command;

• 移除重复的源文件引用：Visual Micro会自动识别并添加库的源文件到编译列表，若你手动在vcxproj中又包含了Command.cpp和Enms.cpp，会导致同一文件被多次编译。打开vcxproj文件，删除<ClCompile Include="..\..\libraries\SWRAntennaLib\src\Command.cpp" />和<ClCompile Include="..\..\libraries\SWRAntennaLib\src\Enms.cpp" />这两行。
• 添加头文件保护：修改Command.h，加入头文件保护宏，避免因多次包含头文件导致的隐式重复声明：

#ifndef COMMAND_H
#define COMMAND_H

// 原Command.h内容不变

#endif // COMMAND_H

• 确认全局实例唯一性：检查项目中所有源文件，确保只有Command.cpp中定义了CommandClass Command;，其他文件仅通过extern CommandClass Command;引用该实例，无重复定义。
• 清理编译缓存：执行Visual Studio的Clean Solution操作，同时删除项目目录下的__vm文件夹和Arduino编译缓存（通常在%LOCALAPPDATA%\Arduino15或项目的build目录），之后重新编译项目。

内容的提问来源于stack exchange，提问作者BedfordNYGuy